In manufacturing airfoils and various other components, relative strain distributions of the airfoils/components must be obtained for quality assurance purposes. Conventionally, such strain distributions have been obtained by positioning strain gauges onto the airfoil/component and performing a lengthy, complicated strain test. However, due to the multiple gauges and/or wires that must be attached to the surface of the airfoil/component, the dynamic characteristics of the airfoil/component may be changed, thereby resulting in strain distributions with significant errors. In addition, the labor costs for performing such strain tests are often prohibitively expensive.
On the other hand, numerical methods for obtaining dynamic mode shape measurements are readily available, which may then be used to determine relative strain by taking spatial derivations of the mode shapes. However, noise in an experimentally obtained mode shape is inevitable. Accordingly, direct spatial derivations will amplify the noise, leading to inaccurate strain calculations.
To remove the noise from experimentally obtained mode shapes, various de-noising methods have been proposed, such as polynomial curve-fitting, Spline, principal component analysis and the like. However, these conventional methods destroy the boundary conditions of the component being tested. As a result, the physics of the problem (corresponding to the mechanical and/or dynamic characteristics of the component) are changed after the use of such methods. This change in physics can lead to a significant error in the “de-noised” mode shape, which is then amplified by taking the derivation of the mode shape in order to obtain vibratory strain.
Accordingly, a system and method for obtaining and accurately de-noising vibratory data of a test component would be welcomed in the technology.